HNF4A expression as a potential diagnostic tool to discriminate primary gastric cancer from breast cancer metastasis in a Brazilian cohort

BACKGROUND Among the many challenges in cancer diagnosis is the early distinction between metastatic cancer and a secondary tumor. This difficulty stems from the lack of markers that offer high sensitivity and specificity and can be easily applied in routine laboratory work. An example of this challenge is distinguishing gastric metastases originating from breast cancer from a gastric primary tumor. Hepatocyte nuclear factor 4 alpha (HNF4A) has been suggested as a potential marker in these cases. The aim of this study was to analyze the expression of HNF4A, estrogen receptor (ER), progesterone receptor (PR) and gross cystic disease fluid protein 15 (GCDFP-15) in a Brazilian cohort. METHODS We performed immunohistochemistry analysis of HNF4A, ER, PR and GCDFP-15 in 126 patients divided into three cohorts: primary breast cancer, primary gastric cancer and both types of tumors. RESULTS Our data confirmed the sensitivity and specificity of the HNF4A marker compared to other currently used clinical markers. CONCLUSION HNF4A alone could be a gold standard marker for distinguishing primary gastric cancer from breast metastasis, thus validating its potential clinical use, especially in populations with high genetic diversity.